[time-nuts] Testing frequency using NTP

Tom Van Baak tvb at LeapSecond.com
Thu Oct 2 20:32:10 EDT 2008

> Tom
> The short term phase instabilities of the sound card LO that occur 
> during the finite interval between the zero crossing times for one 
> channel and the zero crossing time for the other channel can be 
> significant.
> ...


I'm all ears for details about the phase stability of sounds cards.
But you need to define "significant" here. Give me real numbers
and I'll believe it.

Bear in mind that we're talking about a PC-based application with
a couple of milliseconds of expected NTP time jitter, and a modest
goal of measuring frequency to ppm levels even if it takes hours
to achieve that level.


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